Answer:
Blue triangle
Explanation:
x = unknown side
Use the Pythagorean Theorem
Blue triangle:
x² + 5² = √74²
x² + 25 = 74
x² = 74 - 25
x² = 49
x = √49
x₁ = 7, yes
x₂ = - 7, no
Pink triangle:
x² + √18² = 5²
x² + 18 = 25
x² = 25 - 18
x² = 7
x₁ = √7, yes
x₂ = - √7, no
Yellow triangle:
x² + √6² = √43²
x² + 6 = 43
x² = 43 - 6
x² = 37
x₁ = √37, yes
x₂ = - √37, no
Green triangle:
x² + √2² = 4²
x² + 2 = 16
x² = 16 - 2
x² = 14
x₁ = √14, yes
x₂ = - √14, no